The present invention relates to a method of authorizing access to a cellular mobile radio network from a simplified mobile telephone, which is simplified in particular in that it does not include a reader adapted to receive a subscriber identification module, and to a mobile radio system and a simplified telephone for implementing the method.
At present a mobile telephone can be used in a particular cellular network only if it is fitted with a subscriber identification module supplied by the network operator or its distributors and containing information about the user. In the non-limiting case of the pan-European GSM network, the subscriber identification module (SIM) takes the form of a smart card to the ISO standard format or a microcard inserted into a reader in the mobile telephone. The data stored in the SIM card enables the telephone to identify itself to the network. If the network recognizes the data stored in the card, at the end of a phase referred to as xe2x80x9clogging onxe2x80x9d, the user is authorized to use the network, and in particular to make outgoing calls, and can receive calls routed via the network.
An advantage of a SIM card, or more generally of a subscriber identification module, is that it enables the possessor of the module to access the network from any mobile terminal adapted to receive the module.
However, to prevent anyone from using a mobile telephone without the subscriber""s authorization, a particular authentication procedure obliges the user to enter a particular code (PIN) stored in the card when the mobile telephone equipped with the SIM card is switched on. In other words, the mobile telephone cannot log onto the cellular network if the user enters the wrong code.
The number of private persons acquiring a mobile telephone has greatly increased recently. However, these are mostly persons within a predetermined age range. The benefits of being able to contact someone or of being contactable at any time should nevertheless be accessible regardless of age, and in particular to young children.
However, in this context, existing mobile telephones have the following disadvantages:
Installing the SIM card before the telephone is used for the first time can be difficult, especially in the case of a microSIM card.
The authentication procedure previously described can also be complicated for some users, such as young children. It is possible to deactivate this procedure, of course, but its security advantages are then lost.
It is also necessary to be able to control calls made by a child, for obvious cost reasons, and therefore to be able to limit how many numbers can be called from the telephone. Some operators allow for this by offering cards containing a directory with a limited number of entries, so that children can initialize outgoing calls only to a restricted set of numbers.
Finally, apart from the fact that operation of the telephones currently available is complex, they are costly for the user to purchase. It is therefore clearly difficult for parents to invest in a portable telephone for each of their children.
The object of the present invention is to solve the above problems by proposing a method of authorizing access to a cellular mobile radio network from a simplified telephone, simplified in particular in that it does not include a subscriber identification module.
To this end, the present invention provides a method of authorizing access to a public radio network, which method includes the following phases:
a service initialization phase during which a subscriber to the network supplies the network with data representing a serial number specific to a simplified mobile telephone adapted to operate in the network with no subscriber identification module and including means for calling a predefined telephone number and with data characteristic of said predefined telephone number, all of which data is stored in the network;
a phase during which said simplified mobile telephone logs onto said network and, to connect to said service, automatically transmits to the network by radio the data representing the serial number and a first code representing the service number, the network connects to the service and then compares the received data representing the serial number with the stored data representing the serial number, authorizes logging on if there is a match and transmits an authorization code to the simplified mobile telephone by radio, said authorization code being also stored in the network; and
a phase during which said simplified mobile telephone is used to make an outgoing call and activation of said means for calling the predefined telephone number causes the transmission by radio to the network of the first code representing the service number for connecting to said service, said authorization code and a second code representing the called number, the network connects to the service and then compares the authorization code and the second code it has received with the data and the authorization code stored in the network and authorizes the call if there is a match.
The invention also provides a mobile radio system including a public mobile radio network, which system also includes:
a simplified mobile telephone adapted to operate in the network with no subscriber identification module and including means for calling a predefined telephone number;
means for initializing the service whereby a subscriber to said network supplies the network with data representing a serial number specific to said simplified mobile telephone and data characteristic of said predefined telephone number, all of said data being stored in the network;
automatic transmission means specific to said simplified mobile telephone for transmitting to the network by radio the data representing the serial number and a first code representing the service number for connecting to said service;
first means specific to the network for comparing, after connection to the service, the received data representing the serial number with the stored data representing the serial number, authorizing the simplified mobile telephone to log onto the network if there is a match, and then transmitting an authorization code to said simplified mobile telephone and storing that authorization code in the network;
transmission means specific to said simplified mobile telephone for transmitting to the network by radio, following activation of said means for calling the predefined telephone number, the first code representing the service number, for connecting to said service, the authorization code and a second code representing the called number; and
second means specific to the network for comparing, after connection to the service, the authorization code and the second code received with the data and the authorization code stored in the network and for authorizing the call if there is a match.
The invention thirdly provides a simplified mobile telephone including radio signal transmission means for logging onto and making a call in a cellular mobile radio network and means for entering a predefined telephone number, wherein the telephone has a serial number specific to it and during logging on said transmission means transmit a radio signal including data representing said serial number and a first code representing a service number, wherein the telephone further includes means for storing an authorization code sent by the network after logging on, and wherein, during the call to said predefined telephone number, said transmission means transmit a radio signal including the first code, the authorization code and a second code representing the predefined telephone number.